This invention concerns a new acid catalyst comprising (a) a carrier, (b) platinum, (c) a second metal selected from the group consisting of gallium, thallium and indium, (d) tungsten and (e) halogen.
The invention also relates to the use of this catalyst in catalytic reforming reactions and in the production of highly pure aromatic hydrocarbons ("aromizing").
Catalysts containing platinum deposited on a carrier have been known for a long time for use in catalytic reforming. However, in spite of numerous improvements brought to these catalysts up to now, for example by incorporation of such additives as tungsten, molybedenum, rhenium, germanium, iridium, and the like it is still of interest to investigate new catalysts based on platinum which, on the one hand, would give still better yields than those obtained up to now and which, on the other hand, would also have a longer life time than the known catalysts. Moreover, it is desirable to improve the mechanical properties of these catalysts; as a matter of fact, these catalysts are used generally in fixed or moving bed, in the form of conglomerates, for example balls or extrudates of a substantial size so as to promote relatively easy passage of the gaseous reactants. The wear of these catalysts results in the formation of much smaller particles which, progressively, clog the free space and make it necessary to increase the inlet pressure of the reactants or even to discontinue the operation.